[PATCH net-next] genetlink: start to validate reserved header bytes

[Jason A. Donenfeld]

Hi Jakub,

On Wed, Aug 24, 2022 at 05:18:30PM -0700, Jakub Kicinski wrote:
> diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
> index d0f3b6d7f408..0c0644e762e5 100644
> --- a/drivers/net/wireguard/netlink.c
> +++ b/drivers/net/wireguard/netlink.c
> @@ -621,6 +621,7 @@ static const struct genl_ops genl_ops[] = {
>  static struct genl_family genl_family __ro_after_init = {
>  	.ops = genl_ops,
>  	.n_ops = ARRAY_SIZE(genl_ops),
> +	.resv_start_op = WG_CMD_SET_DEVICE + 1,
>  	.name = WG_GENL_NAME,
>  	.version = WG_GENL_VERSION,
>  	.maxattr = WGDEVICE_A_MAX,

FWIW, I wouldn't object to just leaving this at zero. I don't know of
any wireguard userspaces doing anything with the reserved header field.

Jason